In recent years, dengue fever has emerged as one of the most serious vector-borne viral diseases. The molecular biology of dengue virus propagation in the mosquito vector is largely unknown, but the genome sequence, reverse genetic and functional genomics tools as well as high throughput screening methodologies that are now available provide a means of dissecting the mosquito's interactions with the virus in greater detail. In this proposal, we will apply a highly innovative interdisciplinary approach to discover and develop small molecules (compounds) that can render the Aedes aegypti vector mosquito resistant to the virus and thereby incapable of transmitting disease. A previous collaboration between the groups of Drs. Garcia-Blanco and Dimopoulos identified over 300 potential dengue virus host and restriction factors through a high throughput RNAi screen in a Drosophila cell line. We will now expand on these findings and identify homologues of these factors in the Aedes mosquito in specific Aim 1. In Aim 2 we will assess the anti-dengue potential of selected factors in the Aedes cell line and mosquito to select those that are most suitable for small molecule discovery. We will then use a powerful established yeast-based platform to identify compounds that can repress dengue virus host factors, and an established insect cell line -based system to identify compounds that can activate expression of dengue virus restriction factors in Aim 3. In Aim 4 we will test a selected set of these compounds for anti-dengue activity in Aedes cell lines and adult female mosquitoes through different routes of exposure. We will finally investigate the potential influence of selected compounds on mosquito fitness parameters and assess their anti-dengue activity in field -derived mosquito strains in Aim 5. The completion of this highly innovative work will lead to a transition into translational studis on the delivery of potent anti-dengue compounds to natural dengue vector populations, as a prelude towards the development of a novel dengue control strategy.